Potravinarstvo Slovak Journal of Food Sciences
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Influence of suspension liquid total solids on E. coli O157:H7 survival and transfer efficacy between green tomatoes and cardboard
Get PDFThe objectives of this study were: a) to determine E. coli O157:H7 survival on tomatoes and cardboard squares post-drying, stored at 25 ºC in humidified environment for four days, in buffered peptone water (BPW), and 0.1% diluted peptone (DP); b) to determine pathogen transfer rates (0, 1.5, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated cardboard squares and conversely; and c) to evaluate SystemSure Plus ATP luminometer for recognizing contamination on visibly soiled (BPW) or visible clean (DP) cardboard. In tomato inoculation studies, E. coli O157:H7 survived better on the fruit when the inoculum was prepared using DP as compared to BPW. The 1.5-hours post drying counts of 5.34 and 5.76 log10 CFU.mL-1 in the rinsate substantially declined to 1.45 and 1.17 log10 CFU.mL-1 on day four, for DP and BPW, respectively. In cardboard inoculation studies, E. coli O157:H7 persisted for four days, with 1.5-hours post-drying counts and day four counts of 4.53 (DP) and 2.55 log10 CFU.mL-1 (BPW), contrary to 3.81 (DP) and 1.92 log10 CFU.mL-1 (BPW). Under the first impression, the slower die-off of E. coli O157:H7 on cardboard questions the possibility of reusing cardboard boxes due to the potential for cross-contamination. In wet transfer (0 hour drying) trials, both tomato-to-cardboard and cardboard-to-tomato yielded 100% positive transfers irrespective of diluent type. Dry transfer (1.5-hours drying interval post inoculation) from tomato-to-cardboard were 100% positive, but no positives were noted when inoculated, dried cardboard was contacted to tomatoes, irrespective of diluent. Results of transfers with BPW as the diluent showed 100% positive transfer from 24-hours dry tomatoes-to-cardboard, as inoculation spots on the tomatoes remained moist due to hygroscopic nature of solutes in BPW. Conversely, only a 40% positive transfer rate was observed under the same conditions with DP as diluent. No positive transfers were recorded from 24-hours dry cardboard-to-tomatoes, irrespective of diluent type. Though E. coli O157:H7 survived better on the surface of cardboard compared to the surface of tomatoes on day four, the dry transfers were more efficient from tomatoes-to-cardboard than conversely, possibly due to smooth and hydrophobic properties of the tomato, and rough and porous surface of the cardboard. ATP luciferase UltrasnapTM swab test showed 9/9 “pass” results for sterile liquid DP and BPW, while 9/9 “fail” results were observed with liquid peptone and BPW contaminated at ca. 9.0 log10 CFU.mL-1E. coli O157:H7. Cardboard squares treated and dried, with sterile DP, showed 8/9 “pass” ATP luciferase results, and 1/9 “warning”, while cardboard squares with contaminated DP showed 9/9 “fail” result. Cardboard squares treated and dried, with sterile BPW, showed 7/9 “pass” ATP luciferase results, and 2/9 “warning”, while cardboard squares with contaminated BPW showed 9/9 “fail” result. Luminometer can simplify detection of microbial load, as well as organic residues, helping to check cardboard boxes for cleanness
Investigation of consumer behaviour at selected market commodity
Get PDFConsumer behavior is an unexplored area of life for all buyers and sellers alike. Knowledge of consumer behavior brings better market orientation and more consistent establishment of individual products in consumers' shopping baskets. In examining this behavior, the authors of the paper focus on questions such as why, how, where, when, and how much consumers are willing and able to buy at a particular market price. The behavior in question is influenced by several factors (cultural, social, psychological and personality) that influence the final consumer decisions. The main objective of the present document is to evaluate consumer behavior, their purchasing preferences and also to make decisions when buying a particular food product - tea. The primary data were obtained through a questionnaire survey carried out on a sample of 640 respondents. The questionnaire was divided into two basic parts - the demographic part and the part dealing with consumer behavior at the selected market commodity. In the questionnaire processing the respondents were filtered based on their answers. The research has shown that more than 78% of respondents consume tea while women consume it more (50%). Flavor (56.3%) proved to be the most important factor in the selection of a particular tea. Almost half of the respondents reported consuming cut tea (46.5%). In the present document, assumptions were formulated which serve for a deeper analysis of the issue. The relevance of the formulated assumptions was verified by the XLSTAT statistical software. Data were evaluated by qualitative statistics - Chi-square test of good compliance, Fisher's exact test, Mann Whitney test and Friedman test
Authentication of poultry products at the breed level using genetic markers
Get PDFThe Oravka tawny is a Slovak national breed of chicken. This breed has combined utility, which means it is valuable for both its meat and eggs. The Oravka tawny is linked to a specific region, Orava, and therefore these products could be protected by European geographical indication. The labeling and sale of chicken meat by the traditional breed of origin are widely used to promote quality and attract those products in the marketplace. For that use, we created the system and method of authentication that can reliably distinguish between the Oravka tawny, other chicken breeds, and other of Oravka”™s colorful characters. In our research, we analyzed 153 chicken feathers from the Oravka breed as well as from breeds used in the process of breeding the Oravka to their current state. They were divided into nine populations. To separate those populations, we used seven microsatellite markers recommended by FAO (Food and Agriculture Organization) and other authors. To create separate clusters of individual breeds, we used DAPC (discriminant analysis of principal components) analysis
The composition and content of phenolic compounds in tea, grown in humid subtropics of Russia
Get PDFThe article presents the results of studies on the dynamics, qualitative and quantitative composition of phenolic compounds of tea raw materials and tea of new forms of selection of the Institute. The regularity in their synthesis by months is determined, which affects the quality indicators of the end product and necessitates blending to the repaired tea. The accumulation of tannins in tea raw materials depends on hydrothermal conditions, in particular, the amount of precipitation. The content of tannin increases from May to June, then there is some decline in their content, due to hydrothermal stress, slowing the synthesis of tannins in the tea leaf. The content of the water-soluble fraction gradually increases from May to July, and then there is a slight decline. It is shown that the accumulation of phenolic compounds in tea raw materials varies during the collection season. The contents of theaflavins increased from the beginning of the collecting sheet to its completion. The content of thearubigins showed peaks: the lowest rate in June, the highest in August. It was revealed that a sharp drop in the synthesis of thearubigins in June is associated with the onset of the summer dormancy of growth and synthetic processes. The synthesis of both indicators depends on meteorological conditions. The comparative analysis of the samples of tea raw materials collected from experimental plants is carried out. It is shown that the content of tannin and extractive substances in the raw materials of the studied varieties and mutant forms is high. In terms of the ratio of theaflavins and thearubigins, tea made from experienced raw materials meets international requirements. Determination of the qualitative composition of the catechin group of green tea, produced from raw materials of new forms, showed a high level of accumulation of the main groups of catechins
Neuromarketing and the decision-making process of the generation Y wine consumers in the Slovak Republic
Get PDFIn recent years, interest in scholarly research on buying behaviour of Generation Y has grown. However, studies are mainly realized abroad and many of them deal with this issue in general. The purpose of this paper is to identify the factors influencing the decision-making process of the Generation Y customers in the selection of wine in the Slovak Republic. A total of 21 respondents participated in the survey. Eye-tracking and a questionnaire were selected for research. For processing and evaluating the eye-tracking research, the Gazepoint Analysis UX Edition software and Microsoft Excel were used. For statistical data analysis, the Kruskal-Wallis test and Spearman's non-parametric test were performed. Based on the results of the questionnaire and the testing, a label was the most important factor. Differences were noted at the moment of examining the information on a label. The most important factor determined by the questionnaire survey was variety, or vintage year, but by using measurement, the most important factor was label design. With regard to bottle shape, the most preferred was the Bordeaux type of bottle. Testing was carried out in laboratory conditions that only simulated the real selection of wine. This could have caused the difference between conscious decision-making and unconscious visual attention. Therefore, in the future, it is recommended to carry out similar research using a mobile eye camera to realize the test with real wine bottles. It is also assumed to involve other methods to obtain information about real attention of the tested probands. The presented research provides information for winegrowers and merchants who can improve their products and communicate effectively with customers. Findings are particularly beneficial because this research is among the first carried out in this area and it was not based only on conscious participation of respondents, but also on unconscious perception, because a deeper understanding of unconscious influences, that shape consumer's decision, helps to better understand consumer's behaviour
Variation of fruits morphometric parameters and bioactive compounds of Asimina triloba (L.) Dunal germplasm collection
Get PDFThe objective of this study was to evaluate the morphological parameters and bioactive compounds (antioxidant activity, total polyphenol, flavonoid, and phenolic acid content) of 6 genotypes of dry Asimina triloba (L.) fruit from Slovak University of Agriculture in Nitra (Slovakia). Genotypes were obtained from the seeds that were sown in the year 2000. Their morphometric parameters were following: fruit weight from 59.00 to 241.19 g, fruit length from 50.14 to 140.11 mm, fruit diameter from 37.55 to 64.67 mm, number of fruits per cluster from 2 to 8, seed weight from 0.06 to 1.80 g, seed length from 16.33 to 29.11 mm, seed width from 9.56 to 18.33 mm, seed thickness from 4.98 to 9.75 mm, number of seeds in fruit from 4 to 16. The shape indexes of fruits were found ranging from 1.53 to 2.16. The variability of important is the average seeds weight from 7.40 to 35.61%, fruit weight from 14.84 to 32.95%, number of fruits per cluster from 18.21 to 32.54% and a number of seeds in fruit from 13.49 to 27.72%. The other characteristics are more or less stable. Total polyphenol content ranged from 22.13 to 37.36 mg GAE per g, total flavonoid content from 15.10 to 32.03 mg QE per g and phenolic acids content from 0.23 to 0.76 mg CAE per g. All tested samples exhibited DPPH radical scavenging activities with values from 2.84 to 7.04 mg TEAC per g. Antioxidant activity by molybdenum reducing antioxidant power method ranged from 97.25 to 275.41 mg TEAC per g of dry matter. Differences between the genotypes were significant in all observed parameters. This species is potential for propagation and practice used in the Slovak Republic
Functional properties of muffin as affected by substituing wheat flour with carob powder
Get PDFCarob (Cerationa soliqua L.) pod is the good source of dietary fiber, minerals and polyphenolic substances. The aim of this study was to prepare muffin where wheat flour was substituted with carob powder, and determine some physicochemical properties. Carob powder was prepared by milling dry carob pods to particles smaller than 600 μm. Then wheat flour in muffin dough was replaced by carob powder in 5, 10, 15 and 20% (w/w) and subsequently baked at 180 °C for 20 min. It was found that the height of the muffin fortified with carob powder decreased in comparison with that in control muffin sample. Although the height of muffins decreased with the increase in level of carob powder, the differences were not statistically significant. Weight loss was similar for all the muffin samples in this study. Moisture content of muffins with carob powder was significantly higher than that in control. Addition of carob powder had also effect on water activity of muffin. While 0.905 aw was observed in control sample, significantly higher aw values were determinated in fortified muffins (0.912 – 0.923 aw). The antioxidant characteristics were determinated using spectrophotometric assays for total phenolics (TPC), total flavonoids (TFC), radical scavenging activities (DPPH, ABTS) and hydrogen peroxide scavenging (HPS). TPC values gradually increased with the increase in level of carob powder from 348.1 to 829.1 μg gallic acid.g-1 dry matter but TFC values significantly increased in muffin with 15 and 20% (w/w) of carob powder. All the antioxidant assays showed strong and positive association with the increase in level of carob powder. Addition of carob powder resulted in the increase of browning index and FAST index as a metrics of the formation of Maillard products
Gluten-free rice muffins enriched with teff flour
Get PDFIn recent years, demand for gluten-free products has grown. More and more people suffer from allergies, so the market should expand to products for this group of people. It is also important to improve the gluten-free nutritional content diets by incorporating alternative gluten free grains that are naturally rich in nutrients. Teff is a valuable ingredient of gluten-free products because it increases their nutritional quality. Teff is rich in fibre, carbohydrates and has a complete set of essential amino acids, is also high in iron and has more copper, zinc and calcium than other cereal grains. The effect of teff flour addition (25, 50 and 75%) to rice muffins on qualitative and sensory parameters was evaluated. The antioxidant activity of raw materials and products was also determined. Utilization of teff flour up to 50% provided satisfactory results. Incorporation of higher addition levels of teff flour (75%) negatively affected qualitative and textural properties of muffins; the muffins were harder, crumbly and less springy. High antioxidant potential of teff was reflected in increasing antioxidant activity of baked products. Muffins enriched with teff flour had pleasant flavor, sweet and nutty taste. Sensory evaluation revealed that rice muffins incorporated with teff flour at level 25% were the most acceptable for assessors
Antimicrobial activity of resveratrol and grape pomace extract
Get PDFResveratrol is commonly found in food and drinks, including red wine and grapes. Grape extracts have a potent antimicrobial activity in vitro. The antimicrobial activity of plant extracts is the base of their potential application in food preservation agents, pharmaceuticals, cosmetics, alternative drugs and natural therapies. The aim of our study was to evaluate the antimicrobial activity of resveratrol and Blue Frankish pomace extract against Grampositive and Gramnegative bacteria as well as yeasts from the genus Candida. Six bacterial strains (three Grampositive bacteria Staphylococcus aureus CCM 2461, Enterococcus faecalis CCM 4224 and Listeria monocytogenes CCM 4699; three Gramnegative bacteria Escherichia coli CCM 3988, Pseudomonas aeruginosa CCM 1959 and Salmonella enteritidis subsp. enteritidis CCM 4420) and three yeast strains (Candida albicans CCM 8186, Candida krusei CCM 8271 and Candida tropicalis CCM 8223) were evaluated using the antimicrobial assay. Pure resveratrol and grape pomace extracts of red variety Blue Frankish were used. Our results show that resveratrol and red grape pomace extract have a very good antimicrobial activity against Grampositive bacteria when compared with Gramnegative bacteria and yeasts
Effect of weaning system and type of milk flow on milk production of crossbred ewes improved Valachian and Tsigai with Lacaune
Get PDFImproved Valachian (IV x LC; n = 41) and Tsigai (TS x LC; n = 44) crossbred ewes with Lacaune were used to study the effects of three weaning systems on milk production. Prior to parturition, ewes were assigned to one of the following three treatments for the first 53 day of lactation: 1) ewes weaned from their lambs at 24 h postpartum and afterwards machine milked twice daily (MTD), 2) ewes, beginning 24 h postpartum, kept during the daytime with their lambs and allowed them to suckle for 12 h, nights separated from their lambs for 12 h and machine milked once daily in the morning (MIX), and 3) ewes exclusively suckled by their lambs (ES). After the treatment period, lambs were weaned from MIX and ES ewes, and all three groups were machine milked twice daily. Furthermore, ewes were evaluated according to number of live-born and weaned lambs (with one (n = 35) or with two lambs (n = 50)). The measurements of milk yield and milk flow were performed on 110 ±5 day of lactation by the equipment for graduated electronic recording of the milk level in a jar in one-second intervals. No significant differences were observed in the measured values (total milk yield, machine milk yield, latency time, milking time, machine stripping, milk flow rate, and machine milk yield in 30 and 60 s) among weaning treatments and between ewes with one or two lambs and evaluated breeds too. The highest occurrence of one peak milk flow (milk flow without milk ejection) was found out in MTD ewes (50%) compared to MIX (19%) and ES (17%). In conclusion, the different systems of weaning did not influence the milk yield and milk flow parameters in the mid-lactation